Steve from the AAC listening test topic found a bug related to gapless information in m4a files encoded with Winamp/FhG's new AAC encoder.

Updates from the 5.62 release* Fixed a bug that was preventing gapless playback information from being written to the encoded file in some circumstances* Fixed compatibility issue that was preventing HE-AAC files from being used with iTunes* Fixed a bug that was causing the ADTS encoder to fail with the default settings

To install, just unzip this to your Winamp plugins folder. It should overwrite an existing file (unless you are using an older version of Winamp).

This will be released with 5.63 (or 5.621 depending on what version number we decide upon)